Phenol is used in various fields as feedstocks of various synthetic resins such as polycarbonate resin and epoxy resin, including phenol resin, or feedstocks in the pharmaceutical industry, and feedstocks of detergents, such as nonylphenol, or various color paints.
Methods for producing phenol from cumene are well known. For example, the cumene is oxidized using a gas containing oxygen to form cumene hydroperoxide, which is again decomposed under an acidic catalyst, thereby resulting in phenol and acetone.
In the process of generating phenol as above, various side reactions occur at the same time. For example, a trace amount of methanol is generated in the reaction process and included in the acetone product, and the methanol may act as a catalyst poison on BPA reaction of acetone to shorten the lifetime of the catalyst.
Meanwhile, it has been known that it is relatively difficult to separate acetone and methanol, and conventionally, methods have been used, such as a pressure swing distillation process (PSD) for separating highly pure methanol at a pressure of about 1 kgf/cm2g through change of an operating pressure and separating highly pure acetone at a pressure of 10 kgf/cm2g or an extractive distillation process for separating methanol and acetone by means of water having an excellent affinity with methanol as a solvent. However, since the mixture of acetone and methanol forms an azeotrope and the boiling point is reversed at each pressure of 1 kgf/cm2g and 10 kgf/cm2g, at least two or more separation and purification columns were required to separate them and thus there was a problem that the operating cost and the equipment cost of equipments are greatly increased.
Therefore, a distillation method for separating the methanol more effectively is required.